1. The pump impeller and diffuser are showing signs of normal wear. Have a qualified service technician check the impeller and diffuser and replace as necessary.
  2. If the pump is part of a relatively new installation, it could be an electrical problem. Contact a qualified service technician. Have the technician check for loose electrical connections and check the voltage at the pump motor while in operation. The voltage must be within 10% of the motor’s data plate rating. If the voltage is not within 10% contact a qualified electrician and/or the local power service provider.
There is no debris blocking the impeller and the pressure is still low.